In this sequel to "Kamen Rider Genms -The Presidents-", after overcoming the gamer disease, Gai Amatsu used the President Progrise Key to train a Humagear to learn how to become the president of Genm Corporation. As expected, the Humagear gets infected by Kuroto Dan's Bugster Virus and thus, Kuroto Dan gets revived. Gai tries to tell Kuroto of the purpose of his resurrection, but he ignores all reason. Gai acquires a new Driver to achieve his goal. This new Driver transforms Gai into Kamen Rider Thousand Ark, but he is not the only one with new toys as Kuroto also transforms into his new form, Kamen Rider Genm Musou Gamer!